Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is considered a housekeeping protein that is present in virtually all organisms, where it performs metabolic functions essential for survival. GAPDH plays an essential role in the process of energy production, and is also involved in numerous biological processes. GAPDH belongs to a subset of proteins called moonlighting proteins, in which different functions are associated with a single polypeptide chain. The multifunctionality of GAPDH has been described in pathogenic and probiotic microorganisms, in mammals and in plants. In this review, we summarize the moonlighting role of GAPDH in bacteria.